Lab 12 Immune System: 1) Index 2) Introduction 3) Things to Identify 4) Diffuse Lymphoid Tissue 5)Solitary and Aggregated Lymphoid Nodules 6) Tonsils 7) Lymph Node 8) Spleen 9) Thymus 10)Comparison 11) Practical

 

Tonsils

 

# 89 - Tonsil, palatine, human, H & E, 1.5 mm

# 99 - Tonsil, pharyngeal

If needed , see # 100 - Tonsil, palatine, human, H & E, 1.5 mm

 

Tonsils (palatine, lingual and pharyngeal) consist of lymphatic nodules lying in a subepithelial position, separated from underlying tissues by a connective tissue capsule. The lymphoid tissue of the palatine tonsils is penetrated by deep crypts lined by stratified squamous non-keratinized epithelium continuous with the same type of epithelium overlying the palatine tonsils. This epithelium is usually infiltrated and partially masked by a heavy infiltration of lymphocytes.

Do not confuse the epithelium lining the crypts with the connective tissue septa which divides the tonsil into lobules. Locate the ends of the crypts. These may resemble glandular acini when cut transversely

Examine the tonsil at low magnification or with the naked eye to view the distribution of lymphatic nodules. Identify reticular cells within the germinal centers and note the large numbers of mitotic figures within the germinal centers, indicating active production of plasma cells from B-lymphocytes.

What type of epithelium covers the pharyngeal tonsil (slide 99)? Does this also have crypts? What is the name for an enlarged (inflammed) pharyngeal tonsil?

References: Gartner, p. 185, Fig. 3 (palatine tonsil) p. 185, Fig. 4 (pharyngeal tonsil)Ross, p. 354 - 355 p. 171, Fig. 4 (pharyngeal tonsil) Wheater, p. 212, Fig. 11.19 DiFiore, p. 129, Fig. 9-5

 

This is an image taken from the Palatine Tonsils. The way you can determine that this is taken from there is the presence of the Stratified Squamous Non-Keratinized Epithelium, (blue arrow), and the presence of Lymph nodules. The black arrow is pointing to the Germinal Center, and the orange arrow is pointing to the Carona of a secondary nodule with in the Palatine Tonsil.

Blue arrow - Stratified Squamous Non-Keratinized epithelium

Orange arrow - Corona

Black arrow - Germinal Center

 

This is an image taken from the Pharyngeal Tonsils. These have their unique features that distinguish them from palatine tonsils as well. First is the presence of Crypts, indicated by the green arrows. The next characteristic that is important in distinguishing the pharyngeal tonsils is the presence of Psuedostratified Epithelium, indicated by the red arrows. The blue arrows are pointing to a Corona of a nodule found with in the pharyngeal tonsil.

Green arrow - Tonsilar Crypt

Red arrow - Pseudostratified Epithelium

Blue arrow - Corona

 

 

 

 

 

This is a close up of the epithelium of a Pharygeal Tonsil, to give a better view of the Psuedostratified Epithelium, (yellow arrows).

Yellow arrow - Psuedostratified Epithelium

 

 

Palatine Tonsil

Pharyngeal Tonsil

Pharyngeal Tonsil (Epithelium)